Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 232011
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
311 PM CDT Fri Aug 23 2019

.SHORT TERM...(This evening through Saturday)
Issued at 236 PM CDT Fri Aug 23 2019

At 3 PM, scattered to broken fair weather cumulus were found
across the Upper Mississippi River. Temperatures were around 70
north of Interstate 94 and in the lower to mid-70s elsewhere.

Tranquil weather will continue heading into the start of the weekend
as surface ridging across the Great Lakes slowly drifts east. The
surface high will keep a very dry, comfortable air mass in place
over the area. Skies will become mostly clear by early this evening.
Fog will likely develop in some of the river valleys after midnight,
although enough wind off the surface may limit fog development on
the mainstem Mississippi. Temps will fall mainly into the 50s, but
parts of central and north-central WI will likely see 40s, even down
to around 40 in a few of the typical cool spots. Other than some
diurnal cumulus, Saturday looks mostly sunny with highs in the 70s
for most areas and some low 80s in river valleys.

.LONG TERM...(Saturday night through Friday)
Issued at 236 PM CDT Fri Aug 23 2019

On Sunday night, a trough will move northeast out of the Central
Plains into the Upper Mississippi River Valley. Ahead of this
wave, there will be dry air and limited CAPES. As a result, not
anticipating too much rain with its passage.

On Monday, the precipitable water values quickly climb
into the 1.5 to 2 inch range ahead of an approaching cold front.
With plentiful clouds ahead of this front, the 0-1 km mixed layer
CAPES only climb up to 750 J/kg. The GFS generates 35 to 40 knots
of deep (0-6 km) shear south of Interstate 90 on Monday afternoon
ahead of the front. Meanwhile, the ECMWF has very little deep
shear. Overall, prefer the ECMWF and as a result not anticipating
any severe weather with this frontal passage. Precipitation totals
will likely range from the 0.50 to 1.50 inches

Showers move out of the area Monday night/early Tuesday morning,
leaving what looks like a drier day for Tuesday. Slight
precipitation chances return for Wednesday and Thursday night as
a couple of waves cross the area along the periphery of a mid-
level trough over Ontario. Things then look drier to end the week
as the trough finally slides east of the area and high pressure
begins to move in at the surface. Temperatures look to stay near
normal to perhaps slightly below normal by the end the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1135 AM CDT Fri Aug 23 2019

VFR conditions will prevail through Saturday as high pressure
slowly drifts across the area with E/SE winds up to 10 kts.
SCT/BKN diurnal cumulus are expected during the afternoon hours
with mainly clear skies at night. Winds just off the surface
tonight around 15 kts will likely limit fog potential at KLSE
early Saturday.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...JM
LONG TERM...Lee/Boyne
AVIATION...JM


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